Objective: Modest weight loss from clinical interventions improves glycemic control in type 2 diabetes (T2DM). Data are sparse on the effects of weight loss via commercial weight loss programs. This study examined the effects on glycemic control and weight loss of the standard Weight Watchers program, combined with telephone and email consultations with a certified diabetes educator (WW), compared with standard diabetes nutrition counseling and education (standard care, SC). Methods: In a 12-month randomized controlled trial at 16 U.S. research centers, 563 adults with T2DM (HbA 1c 7-11%; BMI 27-50 kg/m 2 ) were assigned to either the commercially available WW program (regular community meetings, online tools), plus telephone and email counseling from a certified diabetes educator, or to SC (initial in-person diabetes nutrition counseling/education, with follow-up informational materials Funding agencies: This study was funded by a grant from Weight Watchers International (WWI) to the Medical University of South Carolina (MUSC). Disclosure: PMO received grants from Orexigen Therapeutics, WWI, and Novo Nordisk; served on advisory groups for Novo Nordisk, Medscape/WebMD, Pfizer, and Janssen; and received honoraria from Novo Nordisk, Vindico CME, and Medscape/WebMD. TAW, KF, PLH, RFK, WTG, DMR, RJM, DW, WJR, and JLS received funding from MUSC to conduct this research at their sites. TAW received grants from Novo Nordisk and Nutrisystem; served on advisory boards for Orexigen Therapeutics, Novo Nordisk, Nutrisystem, and WWI; served as a consultant for Boerhringer Ingelheim; and receives royalties from Guilford Press. KF received research grants from Eisai, EnteroMedics, Novo Nordisk, Orexigen Therapeutics, and Shire; consulted for Eisai, EnteroMedics, Isis Pharmaceuticals, NaZura BioHealth, Novo Nordisk, Takeda, and Zafgen; and served on speaker bureaus for Abbott, Eisai, NPS, and Takeda, and Vivus. PLH consults for Eli Lilly and Novo Nordisk. RFK received personal fees from Novo Nordisk, Takeda, Vivus, and Retrofit. WTG served on advisory boards for Eisai, Novo Nordisk, Daiichi-Sankyo, Liposcience, Vivus, Takeda, Janssen, Boerhringer Ingelheim, and AstraZeneca and conducted research for Eisai, Merck, Sanofi, and AstraZeneca. DMR served on the speaker bureau for Novo Nordisk and received honoraria from Eisai. RJM received grants from Alkames and Janssen. DW received research funding from Bristol-Myers Squibb, Gilead Sciences, Johnson and Johnson (Janssen Pharmaceuticals), Novo Nordisk, Orexigen Therapeutics, Sanofi-Aventis, and Takeda and has received speaker fees. JLS receives research funds from Orexigen Therapeutics. KLH received grants from Novo Nordisk and received speaker fees from Amgen, Astra Zeneca, Eli Lilly, Eisai, Janssen Pharmaceuticals, Novo Nordisk, Sanofi-Aventis, Takeda, and Vivus. JLV is an employee of WWI and holds WWI stock. At the time of this study, KM-K and SLR were employees of WWI and held WWI stock, and they are listed on WWI patents. The other authors declared no conflict of interest. Auth...